James Webb Space Telescope

[RossKean]

Way off topic, but...

Anybody watching this stuff? Christmas Day launch. Will be halfway (distance) to its new home by this evening (6.5 days) but the full journey to the Lagrange L2 point at around 1.5 million km (~1 million miles) takes around 29 days (JWST is currently almost double the distance between Earth and the Moon).

Mission has been almost perfect so far and the JWST has used less fuel than expected during trajectory corrections which means the telescope could outlive its projected ten year lifespan. (In the absence of a mechanical or electronic failure, end-of-life comes when it is out of fuel for maneuvering to stay "on-station".) Several critical deployments have been made successfully so far and the sunshield and mirror itself are scheduled over the next week.

Where's Webb? - Link

I watched most of the launch program on Youtube (2 Hr. +)
(You can skip through the boring parts...)

 

[garauld]

I've been keeping an eye on the happenings. I can't wait for the first images!!

 

[Bugs]

The first image just came in!

 

[RossKean]

I've been keeping an eye on the happenings. I can't wait for the first images!!

29 days to reach its new home and then up to six months to commission, set up instruments and test - assuming everything continues to work as well as it has so far.

https://www.planetary.org/articles/jwst-first-images

 

[RossKean]

Sunshield unfurled successfully.
https://www.space.com/amp/james-webb-space-telescope-sunshield-deployment-success

 

[FjrjrF]

Fascinating, watched it launch from French Guiana near the equator in total cloud cover. Fascinated by the engineering that is dedicated to the rocketry guidance, and also to the payload and it's deployment!

 

[Knifemaker]

Yes, been following this. My daughter works at a planetarium at a college in Washington state.
(She also worked at the St. Louis planetarium and worked at the LIGO observatory (who discovered gravitational waves a few years back))
Keeping my fingers crossed that everything works as designed and waiting to see the first images when fully deployed

 

[RossKean]

Sunshield is deployed. Tensioning originally scheduled for Jan.1 and then they decided to give staff a day off. Was supposed to happen today but press release said they were doing some investigation and it would be delayed another day. No rush at this point - they have another 20 days until they achieve final position - just hope there isn't any problem.

https://www.space.com/james-webb-space-telescope-sunshield-tension-delay

 

[WoodyPecker]

Not that i really understand the physics, but this is just mind-bendingly complex astrophysics how they can figure out this Halo orbit around the L2 point 1.5million Km away into a "dynamically stable" orbital position around the sun/earth system that also fulfills the need to have sun exposure for power (no earth shadowing) while keeping the device sensors fridgedly cold. Love the diagram of sloped gravity wells and last illustration of how it gets to the stable L2 orbit with a balance of potential vs kinetic energy forces. Makes my brain ache, but still fascinating how this can be figgered!

Answer to Why is it necessary for the James Webb telescope to orbit around L2 rather than sit stationary, and how is it possible for it to orbit around nothing given that there is no mass at L2? by Brad Moffat https://www.quora.com/Why-is-it-nec...&share=8dea5773&srid=5mepP&target_type=answer

 

[RossKean]

Answer to Why is it necessary for the James Webb telescope to orbit around L2 rather than sit stationary, and how is it possible for it to orbit around nothing given that there is no mass at L2? by Brad Moffat https://www.quora.com/Why-is-it-nec...&share=8dea5773&srid=5mepP&target_type=answer

I'll bookmark that Quora site and read it after my second cup of coffee. Quora has some pretty good stuff - I have spent a few hours going down some rabbit holes...

 

[mcatrophy]

Granddaughter just sent me this picture of one of her cats in its own gravity well.
(Click on image for larger view)

Buster in a gravity well (or on a bean-bag)​

Sorry, couldn't resist.

 

[RossKean]

Webb mirror deployment is complete!!
Today, they finished unfolding and latching the starboard portion of the primary mirror - port side was deployed yesterday.
https://www.nasa.gov/press-release/nasa-s-webb-telescope-reaches-major-milestone-as-mirror-unfolds
JWST is now 14 days into its 29 day trip to the L2 Lagrange point, 1.5 million km from earth. Almost half way in travel time but 74.5% in terms of distance. All major deployments are complete.
Some further orbital adjustments and then the long process of commissioning (setup, calibration and testing).

https://www.jwst.nasa.gov/content/webbLaunch/whereIsWebb.html?units=metric

 

[RossKean]

Each of the 18 individual mirrors that make up the primary mirror is moveable in order to focus the image onto the secondary mirror. In the next week or so, the mirrors will be moved from their launch positions using the six actuators on each mirror. There is also a separate actuator on each mirror that may be used to adjust the curvature in order to achieve perfect focus. Amazing technology!!
As far as I know, this scheduled mirror movement just puts the mirrors into their approximate positions and fine-tuning is done as part of the final commissioning.
Fascinating stuff!

Individual Mirror Movement - Link

That link has further links to some more interesting reading...

About Webb's adjustable mirrors.
How 18 mirrors see as one.
Mirror Alignment Technology Spinoffs.

 

[RossKean]

Webb made to L2 today with a successful Lagrange insertion burn. Has sufficient on-board fuel for a much longer than expected life - assuming mechanical or electronic difficulties dont crop up. 20 years is a long time.

Won't see any images until telescope is commissioned. Tedious process expected to take 5 months. Mostly optical alignment and focus.

 

[wfooshee]

I like the questions people have of orbiting the L2 point, rather than sitting at the L2 point. Every place I see this mentioned, I see that confusion. Why not park exactly there, and how do you orbit an empty space? That link from WoodyPecker in post 9 is pretty informative, without going completely off the deep end of the physics and mathematics.

 

[Silverbullet]

This stuff has always fascinated me. I still remember watching John Glenns flight as a little kid and have followed the space program ever since. Here is a little something I shot out on my deck earlier this month.

 

[ralph17V]

I have waited many years for the launch of this telescope. It's finally happening

 

[McRide]

Years ago ago I was able to get my 1st look at Saturn close up, and was asked to keep an eye on some very small white smudges off in the distance. As the Scope was reeled in slowly, the smudges became stars that passed by, out of the field of view, as we went deeper and deeper into space. Another very, very distant small smudge started to come into view and eventually Andromeda was revealed. The stars we passed were the outer spiral stars in that galaxy... whew. It was perhaps the 1st time I truly appreciated the vastness of space and how insignificant this planet is.... and I mean 'insignificant planet' in a good, life-sustaining place full of air, water, food and cocktails kind of way, lol.

 

[RossKean]

The technology is absolutely amazing and execution has been pretty much flawless. This would never have been built if there had been any inkling of the extent of cost overrun. Original costs were estimated to be on the order of 1 to 3.5 billion. Current estimates (including lifetime operation) are over $10B. Much of the cost has been for technology development and that is not lost with this one project.

I am anxious to see some of the first images once JWST has been fully optimized - still several months to go...

 

[WoodyPecker]

Ok, next step. First kinda focused image of a star in the Big Dipper. Just 3 out of 7 alignments steps completed and already looks amazing. Note galaxies in the background! Final alignment requires positioning "within a few hundred atomic diameters" on nanometer scale. Makes a micron (millionth of a meter) look like a mile! What kinda motor and linkage technology can achieve that level of precision?? More boggling of the mind
https://www.inverse.com/science/nasa-webb-telescope-star-images